CONN 

S 

43 

.E22 

no.235 


'At?*  ,3^55 


1 


I    NJ    ' 


CONNECTICUT 

Agricultural  Experiment  Station 

NEW  HAVEN,  CONN. 


s 


BULLETIN  235 


FEBRUARY,  1922 


EXPERIMENTS  IN  DUSTING  VERSUS  SPRAYING  ON  APPLES 
AND  PEACHES  IN  CONNECTICUT  IN  1921. 

By  W.  E.  Brittox,    M.   P.  Zavve  and  E.  M.  Stoddard. 


Figure  7.     Apple  Worm 
or  Codling  Moth. 


Figure  8.     Brown  Rot 
of  Peach. 


CONTEXTS 


Page 

Officers  and  Staff 208 

Experiments  in  Dusting  versus 
Spraying  on  Apples  and 
Peaches     in     Connecticut    in 

1021    209 

Apples  210 

Materials   used    210 

Cost  of  Dust  Mixtures 211 

Apparatus  Used 211 

Number  and  Dates  of  Applica- 
tions     211 

Methods  of  Recording  Data  . .  212 

Orchard  Xo.  I    213 

Orchard  Xo.  II   214 

Orchard  Xo.  Ill 215 


Page 

Comparison  of  Different  Sprays  216 

Discussion  of  Results   217 

Chief      Pests     Attacking     the 

Fruit  of  Apple  Orchards  . . .  218 

Insects  218 

Fungous  Diseases 219 

Peaches  221 

Mount  Carmel  Orchard  222 

Cheshire  Orchard 223 

Cost  of  Dusting  and  Sprajong 

Peach  Orchards   224 

Pests   of   the   Fruit   of    Peach 

Orchards  . . .' 22s 

Summarv    226 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Connecticut 
who  apply  for  them,  and  to  other  applicants  as  far  as  the  editions  permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION 

OFFICERS  AND  STAFF 
February,  1922. 


BOARD  OF  CONTROL. 

His  Excellency,  Everett  J.  Lake,  ex-officio,  President. 

James  H.  Webb,  Vice  President Hamden 

George  A.  Hopson,  Secretary Mount  Carmel 

E.  H.  Jenkins,  Director  and  Treasurer New  Haven 

Joseph  W.  Alsop Avon 

Charles  R.  Treat Orange 

Elijah  Rogers - Southington 

STAFF. 
Administration.  E.  H.  Jenkins,  Ph.D.,  Director  and  Treasurer. 

Miss  V.  E.  Cole,  Librarian  and  Stenographer. 
Miss  L.  M.  Beautlecht,  Bookkeeper  and  Stenographer. 
Miss  J.  V.  Beeger,  Stenographer. 
William  Veitch,  In  charge  of  Buildings  and  Grounds. 

Chemistry, 
Analytical  Laboratory.  E.  M.  Bailey,  Ph.D.,  Chemist  in  Charge. 

R.  E.  Andeew,  M.A.,     C.  E.  Shepard,  ^ 

H.  D.  Edmond,  B.S.,    Owen  L.  Nolan,    >  Assistant  Chemists. 

R.  T.  Meewin,  H.  J.  Fisher,  B.A.  j 

Feank  Sheldon,  Laboratory  Assistant. 

V.  L.  Churchill,  Sampling  Agent. 

Miss  Alta  H.  Moss,  Clerk. 

Biochemical  Laboratory.  T.  B.  Osborne,  Ph.D.,  D.Sc,  Chemist  in  Charge. 

Botany.  G.  P.  Clinton,  Sc.D.,  Botanist. 

E.  M.  Stoddard,  B.S.,  Pomologist. 

Miss  Florence  A.  McCormick,  Ph.D.,  Pathologist. 

G.  E.  Graham,  General  Assistant. 

Mrs.  W.  W.  Kelsey,  Stenographer. 

Entomology.  W.  E.  Britton,  Ph.D.,  Entomologist;   State  Entomologist. 

B.  H.  Walden,  B.Agr.,  M.  P.  Zappe,  B.S.,  [Assistant 
Philip  Garman,  Ph.D.,  >      Entomologists. 

John  T.  Ashworth,  Deputy  in  Charge  of  Gipsy  Moth  Work. 
Samuel  T.  Sealy,  Deputy  in  Charge  of  Mosquito  Control. 
Miss  Gladys  M.  Finley,  Stenographer. 

Forestry.  Walter  O.  Filley,  Forester. 

A.  E.  Moss,  M.F.,  Assistant. 
H.  W.  Hicock,  M.F.,  Assistant. 
Miss  Pauline  A.  Merchant,  Stenographer. 

Plant  Breeding.  .Donald  F.  Jones,  S.D.,  Plant  Breeder. 

P.  C.  Mangelsdoef,  B.S.,  Assistant. 

In  charge  of  the 

Tobacco  Station.  G.  H.  Chapman,  Ph.D.,  Windsor,  Conn. 


Experiments  in  Dusting  versus  Spraying  on  Apples 
and  Peaches  in  Connecticut  in  1921. 

By  W.  E.  Britton,  M.  P.  Zappe  and  E.  M.  Stoddard.* 

The  series  of  experiments  with  dusts  in  comparison  with  liquid 
sprays  for  controlling  the  common  insect  and  fungous  pests  of 
apple  orchards  in  Connecticut,  was  begun  in  1920,  and  the  results 
printed  in  the  Report  of  this  Station  for  that  year,  pages  168-177. 
This  project,  considerably  enlarged  and  including  peaches,  was 
continued  in  1921.  In  1920  the  tests  were  all  made  in  one  orchard, 
while  in  1921,  experiments  were  conducted  in  four  apple  orchards 
and  two  peach  orchards,  as  follows : — 

APPLE  ORCHARDS. 

Orchard  No.     I.     Young  orchard,  Station  Farm,  Mount  Carmel        96  trees 

II.     Orchard  of  W.  F.  Piatt,  Orange 97     " 

"      III.     Orchard  of  F.  N.  Piatt,  Milford 524     " 

Old  orchard,  Station  Farm,  Mount  Carmel  . .         40     " 


757  trees 

PEACH  ORCHARDS. 

Station  peach  orchard,  Mount  Carmel   150  trees 

Peach  orchard  of  M.  L.  Coleman,  Cheshire  113     " 


263  trees 


Originally  it  was  planned  to  use  only  the  first  two  apple  orchards 
and  the  peach  orchards,  but  later  we  were  offered  the  use  of  the 
third  apple  orchard.  We  desire  to  express  our  appreciation  and 
thanks  to  the  owners  of  orchards  No.  II  and  III  and  to  Messrs. 
M.  L.  and  Raymond  Coleman  for  their  co-operation  in  this  work; 
also  to  Mr.  B.  A.  Porter  in  charge  of  the  Wallingford  field  station 
of  the  Bureau  of  Entomology,  for  the  use  of  the  dusting  machine, 
and  for  aiding  us  in  making  some  of  the  applications,  and  in  scor- 
ing the  fruit.  Mr.  George  E.  Graham  of  the  botanical  depart- 
ment of  this  Station  assisted  in  applying  some  of  the  treatments,, 
and  Messrs.  B.  H.  Walden  and  Philip  Garman  of  the  entomolog- 
ical department,  and  F.  D.  Luddington,  E.  R.  Barton,  R.  C. 
Botsford  and  J.  R.  Pedersen,  temporary  employees,  aided  in 
gathering  and  scoring  the  fruit. 

The  owners  of  the  orchards  furnished  spray  outfits  with  team 
and  driver  for  each  of  the  spray  applications  in  orchards  II  and 
III. 


*  The  planning  of  these  experiments  and  the  preparation  of  this  paper 
are  the  joint  work  of  the  writers.  The  applications  were  made  by  Messrs. 
Zappe  and  Stoddard,  who  also  supervised  and  took  part  in  the  harvesting 
and  scoring  of  the  fruit. 


2  10       connecticut  experiment  station  bulletin  235. 

Apples. 

materials  used. 
Sprays : — 

The  liquid  spray  for  all  treatments  in  each  of  the  three  apple 
orchards  was  made  as  follows : — 

Liquid  lime-sulphur    3  gallons 

Lead  arsenate  (dry)   3  pounds 

Nicotine  sulphate  (Black  Leaf  40)    24  pint 

Water  100  gallons 

Dusts : — 

SULPHUR-LEAD  DUST. 

Powdered  sulphur 90  parts 

Lead  arsenate  (dry)    10  parts 

This  dust  was  used  only  in  the  eastern  part  of  orchard  No.  Ill, 
and  as  no  treatment  was  given  until  after  the  bloom  was  over  and 
as  aphids  and  red  bugs  were  rather  scarce,  the  nicotine  was 
omitted. 

SULPHUR-LEAD-NICOTINE  DUST. 

Powdered  sulphur 90  parts 

Lead  arsenate   (dry)    10  parts 

Nicotine  sulphate  (Black  Leaf  40)    ...         1  per  cent. 

This  dust  was  purchased  and  should  have  contained  one  per 
cent,  nicotine  sulphate.  During  the  course  of  making  the  appli- 
cations, there  seemed  to  be  considerable  difference  in  the  color  and 
odor  of  the  material  in  some  of  the  containers.  Assuming  that 
this  might  mean  a  difference  in  nicotine  content,  samples  were 
submitted  for  analysis  to  Dr.  E.  M.  Bailey  of  the  chemical  depart- 
ment, who  reported  them  as  follows : 

Sample  Nicotine 

No.  1  .29  per  cent. 

"    2  .30     "       " 

"     3  -84    "       " 

"    4  .71     "      " 

It  will  be  noticed  that  none  of  these  samples  contained  the  full 
amount  of  one  per  cent,  of  nicotine.  As  it  happened,  red  bugs, 
aphids,  and  leafhoppers  were  not  seriously  abundant  in  any  of  the 
orchards  where  this  dust  was  used. 

SANDERS  DUST. 

Hydrated  lime  86  parts 

Dehydrated  copper  sulphate  . .       10    " 
Calcium  arsenate 4    " 

This  dust  was  used  only  in  orchard  No.  Ill  for  the  purpose  of 
comparing  it  with  the  sulphur-lead  dust. 


dusting  and  spraying  of  apples.  211 

Cost  of  Dust  Mixtures. 
The  1 92 1  prices  for  the  dust  mixtures  were  as  follows: 

Sulphur  lead  dust  and  nicotine $13.50  per  hundred 

Sulphur  lead  dust  without  nicotine  ...       8.50     "        " 
Sanders  dust  8.00    "        " 

In  the  dusting  operations,  between  three  and  four  pounds  of  dust 
were  used  per  tree  for  each  treatment.  The  cost  of  dusting  an 
orchard  at  the  present  price  of  materials  is  about  three  times  as 
great  as  spraying  even  though  the  time  required  to  apply  the  dust 
is  very  much  less  than  the  time  required  to  spray.  If  the  price 
of  farm  labor  drops  it  will  mean  a  still  greater  saving  in  favor  of 
the  liquid  spray. 

Apparatus  Used. 

The  dusting  machine  used  in  all  three  orchards  was  a  Niagara 
duster  owned  by  the  Federal  Bureau  of  Entomology,  and  used  at 
its  field  station  in  Wallingford.  The  machine  was  constructed  to 
be  drawn  by  a  team  of  horses,  but  this  method  was  too  slow  when 
moving  the  outfit  from  orchard  to  orchard,  so  the  machine  was 
mounted  on  a  Ford  ton-truck,  thus  saving  considerable  time  on 
the  road  and  in  the  orchard.  The  Ford  truck  had  no  trouble  in 
pulling  this  outfit  through  the  orchards  (see  Plate  XIX,  a). 
When  the  machine  was  not  in  use  it  could  easily  be  unloaded  from 
the  truck  and  stored  in  a  shed. 

An  Arlington  X.  L.  gasoline  power  sprayer  was  used  for  apply- 
ing the  liquid  spray  in  orchard  No.  I.  This  was  a  new  outfit, 
and  the  pressure  was  not  very  high,  running  at  about  ioo  lbs. 
most  of  the  time.  Two  lines  of  hose  were  used  with  a  single 
nozzle  on  each  rod. 

In  orchard  No.  II,  the  liquid  spray  was  applied  with  a  Friend 
gasoline  power  sprayer  equipped  with  a  tank  holding  150  gallons. 
Two  spray  rods  were  used  with  two  nozzles  on  each  rod,  and 
carrying  a  pressure  of  about  200  lbs.  One  man  sprayed  from  the 
ground  and  another  sprayed  from  a  tower  on  the  spray  rig. 

The  spray  outfit  used  in  orchard  No.  Ill  was  identical  with  that 
employed  in  orchard  No.  II,  except  that  instead  of  two  lines  of 
hose  with  double  nozzles,  a  single  line  of  hose  with  a  "spray-gun" 
was  used.  The  pressure  was  about  175  lbs.,  which  is  about  as 
high  as  can  be  used  without  danger  of  mechanical  injury  to  the 
foliage. 

Number  and  Dates  of  Applications. 

Two  treatments  after  blossoming  were  given  in  each  of  the 
three  orchards. 

Orchard  No.  I  had  a  delayed  dormant  spray  of  lime-sulphur  on 
April  7.     On  April  21,  the  pink  treatment  of  spray  and  dust  was 


212         CONNECTICUT   EXPERIMENT    STATION    BULLETIN   235. 

applied.  The  calyx  treatment  was  given  on  May  18  and  19  and 
the  next  or  young  fruit  treatment  was  made  on  June  20. 

Orchard  No.  1 1  had  a  dormant  spray  of  miscible  oil  applied  by 
the  owner.  The  pink  treatment  was  given  April  22.  The  calyx 
treatment  was  made  May  16,  and  the  next  or  young  fruit  treatment 
was  given  on  June  13.  » 

In  orchard  No.  Ill,  no  dormant  treatment  was  given  by  the 
owner,  and  no  pink  treatment  was  made,  as  it  was  too  late  before 
the  orchard  was  offered  to  us  for  experiment.  The  calyx  treat- 
ment was  applied  on  May  16  and  17,  and  the  next  application  or 
young  fruit  treatment  was  given  on  June  14,  15  and  16. 

Method  of  Recording  Data. 

Certain  trees  promising  a  crop  and  situated  inside  the  border  of 
each  plot,  and  representing  the  chief  varieties  upon  which  the  tests 
were  made  in  each  orchard,  were  selected  and  marked  as  count 
trees.  In  orchard  No.  I,  all  trees  were  used  as  count  trees  in 
obtaining  data.  In  orchard  No.  II,  count  trees  were  as  follows : — 
8  sprayed,  6  dusted,  and  7  checks.  In  orchard  No.  Ill,  the  follow- 
ing number  were  used  as  count  trees  : — 12  sprayed,  12  sulphur-lead- 
nicotine  dust,  8  Sanders  dust,  and  7  checks.  For  the  sulphur-lead- 
no  nicotine  treatment,  2  Baldwin  trees  were  used  and  a  composite 
sample  of  Greenings  from  several  trees  because  the  crop  on  this 
variety  was  very  light.  As  a  rule  the  count  trees  were  selected  near 
the  center  of  each  plot  and  not  adjacent  to  a  plot  having  a  different 
treatment,  on  account  of  the  danger  of  spray  or  dust  getting  on 
to  trees  that  were  not  intended  to  be  so  treated.  With  the  liquid 
spray  there  is  little  danger  of  this,  but  the  dust  is  quite  apt  to  drift 
or  be  blown  upon  adjoining  trees. 

The  green  dropped  fruit  from  each  of  the  count  trees  was 
gathered,  counted  and  examined  for  insect  and  fungous  injuries^ 
and  the  data  recorded  for  each  tree,  at  three  different  times  during 
the  season,  as  follows  :  July  11  and  12,  July  25  and  26,  and  August 
8  and  9.  At  harvest  time  the  picked  fruit  was  scored  in  the  same 
manner.  Each  individual  apple  was  carefully  examined  and  a 
record  made  of  each  insect  and  fungous  injury.  Apples  that 
were  called  "good"  were  absolutely  free  from  any  signs  of  insects 
or  fungous  diseases  and  might  better  be  called  "perfect"  for  they 
were  free  from  pests  and  were  perfect  except  possibly  as  to  size. 
An  apple  showing  the  work  of  more  than  one  pest  would  be 
checked  as  many  times  #as  there  were  kinds  of  insect  injury  or 
fungous  diseases.  This  very  often  gave  a  greater  number  of 
injuries  than  there  were  apples  and  in  order  to  get  the  true  amount 
of  any  kind  of  injury  all  the  apples  had  to  be  counted,  and  this 
number  used  to  compute  the  percentage  of  injury  or  the  per- 
centage of  good  fruit.     This  scoring  of  the  fruit  involved  examin- 


DUSTING  AND    SPRAYING   OF   APPLES.  2 1 3 

ing  separately  150,296  individual  apples,  equivalent, to  about  334 
barrels. 

The  figures  given  in  the  tables  of  results  from  the  various  plots 
are  percentages  of  perfect  fruit  or  of  injuries  even  if  very  slight, 
and  cannot  be  compared  with  any  commercial  grading.  For 
instance  an  apple  that  had  been  bitten  by  a  curculio  might  only 
have  one  or  two  small  blemishes  and  would  be  counted  as  a  "cur- 
culio" apple,  but  in  a  commercial  grading  of  the  fruit  would  easily 
go  as  a  No.  1  apple.  The  same  is  true  of  other  injuries,  especially 
small  spots  of  scab,  sooty  blotch  or  fruit  speck.  After  scoring 
the  apples  by  the  above  method,  all  the  fruit  on  several  trees  was 
graded  as  it  would  be  for  market.  The  results  obtained  by  the 
commercial  grading  method  are  of  the  greatest  importance  to  the 
fruit  grower,  and  tell  at  a  glance  which  treatment  gives  the  high- 
est per  cent,  of  No.  1  fruit.  See  Plates  XVII  and  XVIII.  The 
other  method  of  scoring  is  of  value  in  showing  just  where  certain 
treatments  fail. 

The  following  table  has  been  prepared  to  show  how  the  different 
treatments  compare  by  both  methods  of  recording  data. 


Scoring  for  Injuries  versus  Commercial  Grading. 

Scoring  Apples  Singly  Commercial  Grading 


4-1 

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Oi  Sprayed 

48.4 

.4 

42.4 

IO.4 

5.6 

82. 

15.8 

2.2 

B7  Nicotine  Dust 

4-95 

.89 

24.9 

21. 1 

83.6 

46.2s 

46.25 

7-5 

Bn  Sanders  Dust 

•99 

•43 

20.8 

I8.I 

97-5 

60.7 

32.7 

6.6 

Bis  &  C16  Check 

0 

8-43 

32.8 

21.5 

97-7 

20. 

60. 

20. 

D8  Sprayed 

33-2 

1.46 

58.5 

9.9 

4-38 

S3- 

14.2 

2.8 

D14  Nicotine  Dust 

20.2 

6.81 

61.4 

I2.I 

33-05 

66.3 

22.1 

11.6 

Do.  Check 

0 

19.09 

73-9 

12.6 

100. 

II. I 

33-3 

55-6 

Orchard  No.  I. 

Orchard  No.  I  was  the  ten  year  old  Experiment  Station  orchard 
located  at  Mount  Carmel.  This  orchard  is  just  beginning  to  bear, 
and  consists  of  96  trees  on  a  side  hill  sloping  to  the  west.  All  trees 
bearing  fruit  were  used  as  count  trees  to  check  up  results.  The 
varieties  were  Baldwin,  Rhode  Island  Greening,  Roxbury  Russet, 
Mcintosh,  Gravenstein,  Duchess  of  Oldenburg,  Fall  Pippin, 
Northern  Spy,  Sutton  Beauty,  King,  Wealthy,  Hurlbut  and  Stark. 

This  orchard  was  divided  into  three  plots.  The  north  plot  was 
treated  with  liquid  spray  and  the  south  plot  with  the  90-10  nicotine 
dust.  The  remaining  plot  in  the  center  of  the  orchard  was  used 
as  a  check. 


2-14         CONNECTICUT   EXPERIMENT    STATION    BULLETIN    235. 


NUMBER  AND   DATES    OF   APPLICATION. 

The  spraying-  and  dusting  in  each  orchard  was  usually  done  on 
the  same  day  or  on  the  following  day  if  there  was  not  time  enough 
to  finish  the  work  on  the  first  day. 

Before  the  dusting  operations  began  this  orchard  had  a  delayed 
dormant  spraying  of  lime-sulphur  on  April  7  over  the  entire 
orchard.  The  pink  spray  was  applied  on  April  21.  The  weather 
conditions  were  very  favorable  for  dusting  and  spraying  on  this 
day,  there  being  a  very  light  breeze  from  the  southeast.  The  dust 
flowed  very  freely  and  drifted  through  the  orchard  for  quite  a 
distance. 

The  calyx  treatment  was  applied  on  May  18  and  19.  The  spray 
was  put  on  in  the  afternoon  of  May  18,  the  dust  on  the  morning 
of  the  19th.  The  third  treatment  or  young  fruit  spray  was 
applied  on  June  20th.  At  this  time  there  was  no  wind  and  the  dust 
could  be  blown  in  almost  any  direction  and  would  hang  in  the 
orchard  like  a  fog. 

RESULTS   OF   SPRAYING  AND  DUSTING. 

i       %i        s     si     bo  •*       £?  s        i         S         a 

ID  ^  <D  ^    <D  c<D  C   tfl   0)  0)  -4^  ID 

73  O  mo  .20  gO         -S^O         S'==oO  nO  t»oO        ?MO 

O    <D  <D    ID  P.  ID  3    ID  O   °    ID  ->->,d   J2    <D  o    0)  q  ,2    <"  >->    Q.  <" 

OPh  rtO,  <JPl,  OPh  I_SPh         OOmP-i  ooOh  ot«0h         fcc/jdi 

Spray        39.9        .02        1.  48.2        5.78        10.5  1.28        1.7  .27 

Dust  32.5        .00  .99      55-4        6.48  7.2  7.39        1.39       1.40 

Check        24.8        .078      1.09      55.6      22.0  10.5        12.3        15.7      18.0 

DISCUSSION    OF    RESULTS. 

The  liquid  spray  gave  a  higher  percentage  of  good  fruit  than  the 
dust,  and  the  dust  gave  more  good  fruit  than  where  no  treatment 
was  applied.  With  curculio  and  codling  moth  the  spray  gave 
better  control,  while  with  the  other  chewing  insects  the  dust  was 
a  little  better  and  for  some  unaccountable  reason  the  spray  and 
check  plots  gave  the  same  result.  The  amount  of  aphis  and  red 
bug  injury  was  so  small  that  the  figures  are  of  no  particular  value. 
In  the  control  of  the  fungous  diseases,  the  spray  was  of  more  value 
than  the  dust,  but  the  dust  was  much  better  than  the  check. 

Orchard  No.  II. 

This  is  the  same  orchard  and  some  of  the  same  plots  of  trees 
that  were  used  in  the  season  of  1920.  The  orchard  is  about  27 
years  old  and  has  been  very  well  kept.  The  varieties  in  the  experi- 
mental plots  were  Greening  and  Mcintosh,  Fall  Pippin  and  one  tree 
of  Hurlbut.     The  crop  was  very  light  this  year. 

There  were  97  trees  under  experiment,  39  in  the  spray  plot,  49 
in  the  dusted  plot  and  9  in  the  check. 


DUSTING   AND   SPRAYING   OF   APPLES.  215 


TIME   OF    APPLICATIONS. 

The  entire  orchard  had  a  dormant  spray  of  oil  which  was  applied 
by  the  owner.  The  pink  spray  was  applied  on  April  22  and  the 
first  dust  treatment  was  also  applied  on  this  date.  The  calyx  treat- 
ment was  made  on  May  16,  both  liquid  and  dust  being  applied  on 
this  day.     On  June  13,  another  treatment  was  given. 

In  this  orchard  fruit  was  picked  and  scored  from  21  trees,  with 
the  following  result : 

RESULTS   OF   SPRAYING  AND  DUSTING. 


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14-3 

2.4 

5-3 

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3.25 

Check 

i-57 

9-7 

.68 

43-7 

12-3 

11.7 

76. 

66.5 

DISCUSSION    OF    RESULTS. 

As  far  as  the  insects  are  concerned  in  this  orchard,  there  is  not 
much  difference  between  the  dust  and  the  liquid  spray.  The  liquid 
spray  gave  over  twice  the  percentage  of  good  fruit. that  the  dust 
produced,  which  difference  was  largely  due  to  the  number  of 
scabby  apples  in  the  dust  treatment.  In  this  orchard  neither  the 
spray  nor  the  dust  were  very  effective  in  controlling  scab,  due  to 
the  fact  that  the  pink  treatment  was  delayed  too  long  on  account 
of  inclement  weather. 

Orchard  No.  III. 

This  orchard  is  located  about  two  miles  north  of  the  village  of 
Milford  and  is  divided  by  a  highway  running  north  and  south 
through  it.  The  trees  are  about  17  years  old  and  are  on  a  fairly 
level  piece  of  land  with  woods  on  two  sides.  The  trees  had  dense 
crowns  making  it  rather  difficult  to  reach  the  centers  with  spray  or 
dust. 

The  varieties  in  this  orchard  are  Baldwin,  Greening,  Graven- 
stein,  Mcintosh  and  Hurlbut.  This  orchard  had  no  dormant 
spray,  and  afterwards  had  one  treatment  less  than  the  others,  the 
pink  spray  being  omitted. 

t  TIME   OF   APPLICATION. 

The  first  treatment  was  made  at  the  time  the  petals  had  all 
dropped,  on  May  16  and  17.  The  second  application  was  given 
on  June  14,  15  and  16.  The  wind  on  these  days  was  very  strong 
and  the  dusting  work  was  delayed  a  little  on  this  account. 


2l6         CONNECTICUT   EXPERIMENT    STATION    BULLETIN   235. 


RESULTS  OF  SPRAYING  AND  DUSTING. 


Spray- 
Sulphur  Dust  27.4 
Nicotine  Dust  22.6 
Sanders  Dust 
Check 


Good 

Red  Bug 

Aphis 

Curculio 

Codling      Other 

Scab 

Sooty 

Fruit 

Per 

Per 

Per 

Per 

Moth     Chewing 

Per 

Blotch 

Speck 

Cent. 

Cent. 

Cent. 

Cent. 

Per        Insects 
'Cent.    Per  Cent. 

Cent. 

Per 

Cent. 

Per 

Cent. 

44-7 

5-47 

1. 18 

33-9 

5.98          5.98 

4-97 

3-36 

3-28 

27.4 

3-72 

.647 

24.3 

I.85          6.72 

2.08 

34-10 

38.40 

22.6 

12.37 

.706 

40.9 

3-63        9-43 

IO.56 

14.83 

19.70 

16.9 

8.17 

2.03 

36.3 

10.91       11. 13 

13.13 

33.69 

40.70 

4.6 

16.70 

I.24 

60.1 

26.73      30.09 

34-98 

29.87 

35-25 

DISCUSSION    OF   RESULTS. 


As  in  the  other  orchards  the  spray  is  again  better  than  any  kind 
of  dust.  There  are  no  striking  differences  in  the  results  between 
the  three  kinds  of  dust  used.  The  figures  show  less  scab  when 
sulphur  dust  was  used,  but  the  varieties  in  this  particular  plot, 
Baldwins  and  Greenings,  are  not  ordinarily  very  susceptible  to  scab, 
especially  Baldwins.  All  kinds  of  dust  were  less  effective  than 
the  spray  in  controlling  the  fungous  diseases. 

Comparison  of  Different  Sprays. 

In  addition  to  the  work  on  the  comparison  of  dusting  and  spray- 
ing, an  experiment  was  conducted  on  an  orchard  of  40  forty-five- 
year  old  Baldwin  and  Greening  trees  at  the  Station  Farm  in  Mount 
Carmel  in  which  four  different  sprays  were  compared.  This 
experiment  has  been  conducted  for  three  years,  but  as  the  1921 
results  are  representative  of  the  two  previous  season's  results, 
only  the  work  and  results  of  this  season  will  be  discussed. 

materials  used. 

The  sprays  used  in  this  experiment  were  liquid  lime-sulphur, 
dry  lime-sulphur,  B.  T.  S.,  and  Bordeaux  mixture. 

LIQUID   LIME-SULPHUR. 

Lime-sulphur    1  ^2  gallons 

Lead  arsenate  (powder)   ij4  pounds 

Water     50  gallons 

DRY  LIME-SULPHUR. 

Dry  lime-sulphur    3  pounds 

Lead  arsenate    (powder)    l1/*  pounds 

Water  50  gallons 

B.  t.  s. 

B.  T.  S iY2  pounds 

Lead  arsenate   (powder)    i1/*  pounds 

Lime 3  to  4  pounds 

Water    50  gallons 


PLATE  XVII. 


■  ■  '*■   ■  .    * 


66.; 


11.6 


Harvested  fruit  from  orchard  No.  I.     Sprayed  fruit  at  top,  dusted  fruit 

in  center,  and  check  or  untreated  fruit  at  bottom.     The  percentage  of 

fruit  in  each  grade  is  shown  on  the  labels. 


COMMERCIAL  GRADING  OF  APPLES  FROM   EXPERIMENT  PLOTS. 


PLATE  XVIII. 


Harvested  fruit  from  orchard  No.  III.     Sprayed  fruit  at  top,  Sander's 

dust  in   second  view,   sulphur-lead-nicotine  dust  in  third  view,  and 

check  or  untreated  fruit  at  bottom.     The  percentage  of  fruit  in  each 

grade  is  shown  on  the  labels. 


COMMERCIAL  GRADING  OF  APPLES  FROM  EXPERIMENT  PLOTS. 


PLATK  XfX. 


a.     Dusting  outfit  used  in  experiments. 


b.     Spraying  outfit  used  in  orchard  No.  II. 
DUSTING  AND  SPRAYING  IN  APPLE  ORCHARD. 


PLATE  XX. 


a.     Adult  moth  resting  on  young  apple,  twice  enlarged. 


b.     Stem,  calyx  and  side  injury:    section  of  fruit  showing  larva  in  burrow. 

Natural  size. 


CODLING  MOTH. 


PLATE  XXI. 


a.     Adult  red  bug.     Four 
times  enlarged. 


b.     Apple  injured  by  red  bugs. 
Natural  size. 


c.     Curculio  egg-scars  as  they  appear  at  harvest  time. 
Natural  size. 


d.     Plum  curculio  side  view. 
Four  times  enlarged. 


e.     Spots  on  apple  leaf  caused  by  black  rot  fungus. 
Natural  size. 


RED  BUG,  CURCULIO    AND  BLACK   ROT. 


PLATE  XXII. 


a.     Peach  Scab. 


c.     Fruit  speck  of  apple. 


b.     Brown  rot  of  peach. 


d.     Black  rot  of  apple. 


ppipjtf* 


e.     Apple  scab.  f.     Sooty  blotch  of  apple. 

FUNGOUS  DISEASES  OF   PEACH   AND  APPLE. 


DUSTING   AND    SPRAYING   OF   APPLES. 


217 


BORDEAUX   MIXTURE. 

Copper  sulphate 1  pound 

Lime 4  pounds 

Lead  arsenate  (powder)   1J/2  pounds 

Water 50  gallons 

APPARATUS    USED. 

All  the  applications  were  made  with  an  Arlington  X.  L.  outfit, 
using  two  lines  of  hose  and  rods  with  one  Friend  nozzle  to  each 
rod.     This  outfit  maintained  a  pressure  of  125  pounds. 

DATES    OF    APPLICATION. 

The  entire  orchard  had  a  delayed  dormant  spray  of  lime-sulphur 
1-9  on  April  7.  As  scab  was  known  not  to  be  abundant  in  this 
orchard,  the  pink  spray  was  omitted.  The  calyx  spray  was  put 
on  May  19  and  the  young  fruit  spray  on  June  20. 

The  following  table  shows  the  results  obtained. 


RESULTS  OF   SPRAYS. 


Dry  Lime-Sulphur 
Liquid  Lime-Sulphur  53.6 
B.  T.   S. 
Bordeaux 


Good 

Per 

Cent. 

Red  Bug 

Per 

Cent. 

Aphis 
Per 
Cent. 

Curculio 
Per 
Cent. 

Codling    Other 
Moth     Chewing 
Per        Insects 
Cent.    Per  Cent. 

Scab 
Per 

Cent. 

Sooty- 
Blotch 
Per 
Cent. 

Fruit 

Speck 

Per 

Cent. 

72.5 
-53.6 

•13 
.14 

I.24 
I.67 

10.70 
21.76 

.66 
5-43 

8.7 
17.70 

•03 

.66 

8.42 
5-24 

3.64 

2.66 

54-2 
52.0 

•34 

•25 

3-09 
1.8 

22.92 
23.82 

4.92 
8.29 

11.64 
n.85 

•34 
1.78 

13.24 
9.08 

4-57 
3-86 

DISCUSSION    OF   RESULTS. 

In  this  experiment  the  dropped  fruit  was  not  scored  and  records 
were  made  from  harvested  fruit  from  all  trees,  otherwise  the  data 
was  taken  as  described  elsewhere  in  this  paper.  The  check  trees 
did  not  bear  any  fruit  so  no  comparison  could  be  made  with 
untreated  trees.  It  will  be  seen  that  the  dry  lime-sulphur  gave 
the  highest  per  cent,  of  good  fruit,  this  also  being  true  in  the  two 
previous  seasons'  work  with  this  material.  Not  only  was  there 
a  higher  per  cent,  of  good  fruit  but  the  appearance  and  finish  of 
the  fruit  was  superior  to  that  from  the  other  plots.  The  B.  T.  S. 
gave  about  the  same  control  of  fungous  and  insect  pests  as  did  the 
lime-sulphur  but  the  fact  that  it  caused  considerable  injury  to  the 
foliage  makes  it  an  undesirable  material  to  use.  It  was  estimated 
that  it  caused  a  drop  of  from  30  to  40  per  cent,  of  the  foliage,  as 
compared  with  no  injury  from  any  of  the  other  treatments. 

Usually  there  has  been  considerable  russetting  of  the  fruit  on 
the  Bordeaux  plot  and  probably  this  year  was  no  exception,  but  on 
account  of  the  fact  that  late  frosts  caused  more  or  less  russetting 
of  the  fruit  on  all  of  the  plots,  it  was  not  possible  to  get  any  data  on 
this  point.  Because  of  its  tendency  to  russet  the  fruit,  we  do  not 
recommend  Bordeaux  as  a  spray  for  apples. 


2  [8       connecticut  experiment  station  bulletin  235. 
Chief  Pests  Attacking  the  Fruit  of  Apple  Orchards. 

INSECTS. 

Codling  Moth: — This  is  the  chief  insect  attacking  apple 
orchards  and  though  varying  in  abundance  is  present  every  year 
in  every  orchard.  It  passes  the  winter  as  a  larva  in  the  cocoon, 
transforming  to  a  pupa  in  the  spring.  The  moths  emerge  soon 
after  the  trees  blossom  and  lay  their  eggs  chiefly  on  the  leaves, 
though  sometimes  on  branches  and  developing  fruit.  The  egg- 
laying  period  extends  over  several  weeks,  and  in  about  a  week 
these  eggs  hatch,  and  the  larvae  feed  slightly  on  the  foliage  but 
tunnel  into  the  fruit  mostly  through  the  calyx.  They  eat  their 
way  to  the  core,  and  later  burrow  to  the  surface  making  the  tra- 
ditional worm  hole,  as  shown  on  Plate  XX,  b.  From  20  to  30  days 
are  required  for  larval  development,  when  the  worms  leave  the 
fruit  usually  before  it  falls,  and  seek  a  protected  place  to  spin  the 
silken  case  or  cocoon.     Of  those  assuming  this   stage  in  mid- 


Figure  9.     The  Plum  Curculio. 

summer,  a  portion  transform  the  same  season,  while  those  going 
into  their  cocoons  late  in  summer  or  autumn  do  not  emerge  as 
adults  until  the  following  season.  There  is  usually  one  full  genera- 
tion, and  a  partial  second  each  year  in  Connecticut. 

The  codling  moth  is  usually  less  injurious  in  orchards  which  are 
sprayed  each  year  with  arsenical  poisons. 

Plum  Curculio: — The  adult  is  a  weevil  or  snout  beetle  which 
hibernates  in  rubbish  heaps,  hedgerows,  woodlands,  et  catera, 
where  it  can  find  protection.  It  appears  on  trees  soon  after  the 
buds  open,  and  soon  after  the  fruit  sets  and  the  petals  drop  begins 
to  puncture  the  young  fruit.  Two  kinds  of  punctures  are  made, 
one  for  feeding  and  the  other  for  depositing  eggs.  The  latter  are 
crescent-shaped  and  the  egg  is  placed  just  under  the  skin  of  the  flap 
on  the  concave  side  of  the  crescent.  Egg-laying  may  extend 
over  nearly  the  whole  season,  though  most  of  them  are  laid  during 
the  first  month  after  the  blossoms  fall.  The  feeding  punctures 
are  small  cavities  eaten  into  the  surface  of  the  fruit  and  usually 
occur  in  clusters.  They  may  be  made  late  in  the  season.  There 
is  only  one  generation  each  year,  and  this  insect  usually  breeds  in 


PESTS  OF  FRUIT  OF  APPLE  ORCHARDS.  219 

stone  fruits.  The  larvae  do  not  develop  in  the  apple,  and  the 
only  injury  is  that  caused  by  the  punctures.  Plate  XXI,  c,  shows 
the  egg-scars  as  they  appear  on  the  fruit  at  harvest  time.  The 
application  of  poisons,  though  of  some  benefit,  is  not  a  satisfactory 
control  for  this  insect.  Much  more  can  be  accomplished  by 
abolishing  its  hibernating  places,  like  rubbish  heaps,  hedgerows, 
et  ccetera,  in  or  near  the  orchard. 

Other  Chewing  Insects: — Many  insects  might  be  included 
under  this  head,  but  only  a  few  will  be  mentioned  in  connection 
with  the  orchards  where  our  experiments  were  conducted. 

Apple  Maggot: — This  was  not  a  serious  pest  in  these  orchards, 
though  present  and  causing  some  injury  on  certain  varieties. 
Later  treatments,  so  that  the  foliage  and  fruit  will  be  coated  with 
poison  during  July,  may  be  effective  in  poisoning  the  adults  before 
they  lay  eggs. 

Leaf-Rollers: — In  1920,  there  was  considerable  surface  injury 
to  fruit  late  in  the  season  caused  by  the  red  banded  leaf-roller 
Eulia  velutinana  Walker,  and  the  lesser  apple  worm  Enarmonia 
prunivora  Walsh.  Consequently  some  later  treatments  were 
given  a  portion  of  some  of  the  plots,  but  these  insects  were  not 
noticed  in  1921,  and  the  treatments  gave  no  benefit. 

Aphids: — The  green  apple  aphid  Aphis  pomi  DeGeer,  and  the 
rosy  aphid  Anuraphis  malifoliae  Fitch  (Aphis  sorbi  Kalt.)  were 
not  prevalent  in  the  experiment  orchards  in  192 1.  Some  eggs 
hatched,  but  the  aphids  soon  disappeared,  perhaps  on  account  of 
cold  storms,  lady  beetles,  or  other  natural  agencies,  and  caused  no 
appreciable  injury.  For  this  reason  no  marked  benefit  can  be 
shown  by  the  treatment  against  these  insects.  The  eggs  hatch 
at  about  the  time  that  the  leaf  buds  begin  to  unfold.  Nicotine 
sulphate  in  the  delayed  dormant,  pink  and  calyx  treatments  should 
control  these  aphids. 

Red  Bug: — The  false  apple  red  bug  Lygidea  mendax  Reut. 
was  not  abundant  in  any  of  the  experiment  orchards  in  1921,  but 
was  more  prevalent  in  orchard  No.  ill  than  elsewhere.  Here  and 
also  in  orchard  No.  II  the  check  plots  showed  much  more  injury 
than  the  treated  pnes.  The  eggs  hatch  just  before  the  blossoms 
open  and  nicotine  sulphate  in  the  pink  treatment  and  in  the  calyx 
treatment,  if  thoroughly  applied,  should  kill  most  of  the  nymphs. 

Fungous  Diseases. 

Scab : — Scab  was  very  prevalent  during  the  past  season  in  most 
orchards.  This  can  probably  be  accounted  for  in  two  ways  ;  first, 
the  mild  winter,  which  allowed  the  fungus  to  carry  over  in  good 
condition  on  the  old  leaves  and  mature  a  large  crop  of  spores 
which  infected  the  young  foliage  early  in  the  spring,  and  second  the 
fact  that  there  was  a  rainy  spell  which  was  most  favorable  for 


2  20         CONNECTICUT   EXPERIMENT   STATION    BULLETIN   235. 

scab  infection  and  which  prevented  putting  on  the  pink  spray  at 
the  proper  time.  Under  Connecticut  conditions  the  pink  spray  is 
the  important  spray  for  scab  control  and  on  varieties  which  are 
particularly  susceptible  it  would  seem  desirable  to  put  on  two 
sprays  after  the  leaves  come  out  and  before  the  blossoms  open.  It 
seems  to  be  the  consensus  of  opinion  among  plant  pathologists 
that  it  is  not  feasible  to  attempt  to  treat  or  destroy  the  leaves  under 
the  trees,  on  which  the  scab  carries  over  winter,  but  rather  to 
control  it  by  proper  and  timely  spraying.     See  Plate  XXII,  e. 

Black  Rot: — Black  rot  was  more  prevalent,  especially  on  the 
foliage,  during  1921  than  usual.  This  disease  was  present  to  a 
greater  or  less  extent  in  all  the  orchards  which  were  observed  dur- 
ing the  season  and  probably  these  represent  a  general  condition 
throughout  the  State.  Usually  Baldwin  was  the  variety  most 
susceptible,  although  other  varieties  showed  some  infection.  In 
one  orchard  only  was  any  serious  damage  done  and  in  this  only  a 
small  number  of  trees  were  severely  attacked. 


Figure  10.    Apple  Scab. 

On  the  leaf  the  black  rot  fungus  makes  small  dark  brown  cir- 
cular spots  and  later  causes  the  leaf  to  turn  yellow  and  drop  pre- 
maturely. This  fungus  also  attacks  the  fruit,  making  a  brown 
rotting  of  the  flesh  of  the  apple,  which  form  of  infection  was  noted 
in  a  few  cases,  but  nowhere  did  any  serious  damage  result.  The 
Hurlbut  seemed  to  be  more  susceptible  to  fruit  infection. 

This  fungus  does  not  usually  do  any  great  amount  of  damage  in 
Connecticut  and  if  present  should  be  controlled  by  the  ordinary 
spraying  schedule.  The  infection  on  the  foliage  evidently  takes 
place  early  in  the  season,  making  the  pink  spray  important  in  its 
control.  This  fungus  is  shown  on  the  leaf  on  Plate  XXI,  e,  and 
on  the  fruit  on  Plate  XXII,  d. 

Fruit  Speck: — Fruit  speck  or  "Brook's  spot"  is  a  fruit  disease 
and  causes  the  very  small  irregular  black  spots  on  the  skin  of  the 
apple  which  on  light  skinned  varieties  are  usually  bordered  with 
red,  the  spots  occurring  most  abundantly  near  the  calyx  end. 
This  disease  should  not  be  confused  with  "Baldwin  spot"  which 
is   a   physiological   trouble   characterized   by   brown   corky   spots 


DUSTING   AND    SPRAYING   OF  PEACH    ORCHARDS.  22  1 

scattered  through  the  tissue  of  the  fruit.  Fruit  speck,  being  a 
fungous  disease,  can  be  controlled  by  spraying  with  a  fungicide 
while  the  "Baldwin  spot"  is  not  affected  by  such  applications. 
To  control  fruit  speck  successfully,  the  spraying  should  be  done 
very  thoroughly.  The  fruit  speck  fungus  does  not  injure  the 
quality  of  the  fruit  but  spoils  its  appearance,  and  makes  an 
entrance  for  various  decay  organisms. 


Figure  n.     Sooty  Blotch  of  Apple. 

Sooty  Blotch: — This  disease  is  one  of  the  most  common  apple 
diseases  and  is  probably  one  of  the  easiest  to  control  by  spraying, 
yet  it  seems  to  be  true  that  less  attention  is  paid  to  it  than  to  other 
troubles,  for  instance,  a  grower  will  be  much  alarmed  at  a  heavy 
scab  infection  but  will  almost  consider  sooty  blotch  a  necessary 
adjunct  to  the  finish  of  his  fruit.  The  sooty  blotch  fungus  grows 
entirely  on  the  skin  of  the  apple  and  does  no  harm  except  to 
injure  its  appearance  seriously,  as  is  shown  on  Plate  XXII,  f . 

PEACHES. 

In  addition  to  the  experiments  with  dusts  and  sprays  in  apple 
orchards,  experiments  were  conducted  to  test  the  comparative 
values  of  dusting  and  spraying  on  peaches.  Two  orchards  were 
used,  one  at  Mount  Carmel  owned  by  this  Station,  and  the  other 
in  Cheshire,  owned  by  Mr.  M.  L.  Coleman. 

Apparatus  and  Materials  Used. 

In  the  spraying  of  both  orchards,  an  Arlington  X.  L.  power 
sprayer  with  a  ioo  gallon  tank  was  used,  carrying  two  lines  of 
hose  with  one  nozzle  on  each  rod,  at  a  pressure  of  about  125 
pounds.  The  dusting  machine  used  at  Mount  Carmel  was  a 
Niagara  duster,  being  the  same  one  that  was  used  in  the  apple 
dusting  experiments.  The  duster  used  at  Cheshire  belonged  to 
Mr.  Coleman,  and  was  also  a  Niagara  machine. 


222  CONNECTICUT    EXPERIMENT    STATION    BULLETIN    235. 

The  spray  material  used  in  both  orchards  was  atomic  sulphur, 
at  the  rate  of  10  pounds  to  100  gallons  of  water.  The  dust  used 
at  Mount  Carmel  was  ordinary  dusting  sulphur,  and  at  Cheshire 
the  dust  used  for  the  first  two  applications  was  a  70-20-10  mixture, 
70  parts  of  sulphur,  20  parts  of  lime  and  10  parts  of  lead  arsenate. 
For  the  third  dusting  at  Cheshire,  the  lead  arsenate  and  lime  were 
omitted. 

Method  of  Recording  Data. 

In  the  peach  experiments,  the  dropped  fruit  was  not  gathered 
and  scored  as  was  the  case  with  the  apples.  No  count  trees  were 
selected  here,  but  a  record  taken  from  every  tree  which  bore  fruit. 
In  harvesting,  several  pickings  were  made  and  each  fruit  examined 
and  injuries  recorded.  This  necessitated  the  examination  of 
120,063  individual  fruits,  or  about  1,715  baskets. 

» 

Mount  Carmel  Orchard. 

This  orchard  is  ten  years  old,  planted  on  the  brow  of  a  hill  slop- 
ing toward  the  west,  and  comprises  150  trees  planted  in  five  rows 
of  30  trees  each.  The  varieties  which  were  used  in  this  orchard 
are  Elberta,  Carman,  Champion,  Mountain  Rose  and  Greensboro. 
The  orchard  was  divided  into  three  plots,  the  north  plot  was 
sprayed,  the  south  plot  dusted  and  the  center  plot  left  untreated  for 
a  check. 

Three  applications  of  spray  and  dust  were  made  in  this  orchard, 
the  first  on  May  18th  when  the  "shucks"  had  all  dropped  from 
the  young  fruit;  the  second  on  June  16th  and  the  last  on  July  13th 
and  14th.  The  dust  used  was  the  regular  dusting  sulphur  with 
no  lead  arsenate  or  lime  added.  The  liquid  spray  used  was  atomic 
sulphur,  10  pounds  to  100  gallons  of  water,  with  no  lead  arsenate. 
As  no  arsenical  poison  was  used  in  this  orchard,  and  as  there  was 
practically  no  scab,  the  only  injuries  recorded  were  those  caused  by 
brown  rot. 


DUSTING   AND    SPRAYING    OF  PEACH    ORCHARDS.  223 


RESULTS  OF  TREATMENT. 


Good  Fruit 

Rot 

Per  Cent. 

Per  Cent 

Elberta : 

Spray- 

98.6 

1-34 

Dust 

99-6 

.36 

Check 

99.6 

.38 

Carman: 

Spray- 

93- 

7.2 

Dust 

97-5 

2-5 

Check 

No  Checks  for  this  variety 

Champion : 

Spray 

89-3 

10.7 

Dust 

98.4 

1.6 

Check 

96.5 

34 

Mt.  Rose : 

Spray 

88.2 

1 1.8 

Dust 

99.2 

.88 

Check 

98.5' 

1.6 

Greensboro : 

Spray 

79-9 

20.1 

Dust 

87.5 

12.7 

Check 

No  Checks  for  this 

variety 

Discussion  of  Results. 

On  all  varieties  the  dust  was  more  effective  in  controlling  brown 
rot  than  the  spray.  The  amount  of  scab  and  curculio  injury  was 
so  slight  that  no  data  was  taken.  The  check  trees  in  this  orchard 
had  better  fruit  than  the  sprayed  trees  because  the  trees  were  close 
together  and  the  check  trees  were  north  of  the  dusted  plot  and  at 
every  application  of  dust  the  wind  was  from  the  south  or  south- 
west, thus  blowing  the  dust  onto  the  check  trees. 

Cheshire  Orchard. 

This  orchard  is  about  the  same  age  as  the  Mount  Carmel  peach 
orchard.  Because  of  the  size  of  the  orchard,  only  a  portion  con- 
taining two  varieties,  Carman  and  Elberta,  was  used  in  the  spray- 
ing and  dusting  tests.  Mr.  Coleman,  the  owner  of  the  orchard, 
has  been  dusting  peaches  for  several  years  with  satisfactory 
results,  and  this  year  he  dusted  all  of  his  orchard  except  that  por- 
tion where  the  sprayed  plot  was  located.  The  records  of  the  dust- 
ing were  taken  from  a  portion  of  the  orchard  adjacent  to  the 
sprayed  plot.  A  few  trees  on  the  edge  of  the  orchard  at  the  end 
of  the  sprayed  plot  were  left  without  treatment  as  checks.  One 
hundred  and  thirteen  trees  were  included  in  the  three  plots. 

This  peach  orchard,  like  the  other,  was  given  three  treatments 
of  spray  and  dust,  on  the  following  dates :  May  22,  June  18  and 
July  13.  The  spray  used  was  atomic  sulphur,  10  pounds  to  100 
gallons  of  water.     No  lead  arsenate  was  used  in  the  liquid  spray. 


224  CONNECTICUT    EXPERIMENT    STATION    BULLETIN    235. 

The  liquid  spray  was  applied  with  the  same  outfit  as  was  used 
at  Mount  Carmel.  The  outfit  was  carried  to  Cheshire  on  a  Ford 
truck  to  save  time.  On  arriving  at  Cheshire  the  sprayer  was 
unloaded  and  a  horse  used  to  draw  it  about  the  orchard,  as  the 
trees  were  too  close  to  allow  the  truck  to  pass  through  the  orchard. 
Five  pickings  were  made  of  Carman,  August  10,  12,  14,  16  and 
19,  and  four  of  Elberta,  September  2,  5,  7  and  9.  There  was  con- 
siderable, scab  in  this  orchard,  so  records  were  made  of  light  and 
heavy  infestations  of  scab,  together  with  rot  and  curculio. 


RESULTS   OF  TREATMENT. 


Elberta : 


Carman : 


Good 
Per  Cent. 

Rot 
Per  Cent. 

Light  Scab 
Per  Cent. 

Heavy  Scab    Curculi 
Per  Cent.    Per  Cem 

Spray 

Dust 

Check 

65- 

69.9 

174 

2.66 
5-24 
5.8l 

27-39 
22.4 

58.4 

1.2                 S.52 

•94               3-24 
17.6                  2.91 

Spray 

Dust 

Check 

37-4 

56/ 

27-3 

7.15 
492 
16.5 

43-2 
27.4 
38.2 

12.12               4.61 

9-4              5-12 
21.7              4-53 

It  will  be  noted  that  on  both  varieties  the  dust  gave  a  higher 
percentage  of  good  fruit  than  the  spray,  largely  through  the  more 
effective  control  of  rot  and  scab.  The  lead  arsenate  in  the  dust 
did  not  control  curculio  to  any  appreciable  extent.  For  some 
unknown  reason  the  curculio  injury  was  less  in  the  check  plot  in 
both  varieties  than  in  either  the  dusted  or  sprayed  plot.  Peaches 
scored  as  "light  scab"  had  only  a  small  amount  of  scab,  and  would 
be  graded  as  No.  I.  Those  scored  "heavy  scab"  would  not  be 
included  in  a  No.  I  grade.  Most  of  the  peaches  in  the  curculio 
column  would  undoubtedly  be  included  in  a  No.  I  grade. 

Cost  of  Dusting  and  Spraying  Peach  Orchards. 

The  price  of  dusting  sulphur  without  lead  arsenate  used  for 
dusting  the  peach  orchards  was  $3.75  per  100  pounds  in  1921,  and 
the  cost  of  atomic  sulphur  in  100  pound  lots  was  $12.75.  Allow- 
ing one  pound  of  dust  and  one  gallon  of  spray  per  tree  the  cost  is, 
dust  324  cents  per  tree,  spray  1%.  cents  per  tree  for  one  treat- 
ment only.  There  would  be  quite  a  saving  of  time  in  favor  of  the 
dust  which  would  partly  offset  the  higher  cost  of  material  and 
make  the  treatments  more  nearly  equal  in  price.  However,  it  is 
doubtful  if  it  would  pay  to  dust  peaches  unless  a  large  acreage  was 
to  be  treated  so  that  enough  time  could  be  saved  to  make  an  appre- 
ciable cut  in  the  labor  cost.  It  would  be  necessary  to  have  a  spray 
outfit  for  the  dormant  treatment  and  the  extra  cost  of  the  duster 
would  probably  not  be  offset  by  the  saving  of  time  and  slightly 
better  results  on  a  small  orchard. 


PESTS   OF   THE   FRUIT   OF    PEACH    ORCHARDS.  225 


Pests  of  the  Fruit  of  Peach  Orchards. 

insects. 

Plum  Curculio: — The  curculio  is  unquestionably  the  most 
important  insect  attacking  the  fruit  of  the  peach.  This  insect  has 
already  been  discussed  on  page  218  as  an  apple  pest.  In  the 
peach  fruit,  the  larvae  develop  to  maturity  and  transform.  Most 
of  the  infested  fruits  drop  early  and  therefore  do  not  show  at 
harvest  time,  though  the  egg-laying  and  feeding  punctures  are 
often  apparent.  Curculio  can  best  be  controlled  by  getting  rid  of 
all  hibernating  places  near  the  orchard.  Arsenical  applications, 
though  a  help,  should  not  be  depended  upon  as  the  only  means  of 
control. 

FUNGOUS   DISEASES.- 

Brown  Rot: — Brown  rot  is  the  most  serious  fungous  disease 
that  the  peach  grower  has  to  contend  with,  but  it  can  be  controlled 
by  thorough  and  timely  treatment.  Usually  this  is  a  disease  of 
the  fruit  but  under  favorable  conditions  such  as  obtained  in  the 
spring  of  1921,  serious  infection  of  the  blossoms  on  early  varieties 
is  likely  to  take  place.  Such  infection  not  only  kills  the  blossom 
but  forms  a  canker  which  often  girdles  and  kills  the  entire  branch. 

The  blossom  and  twig  infection  seems  to  be  worst  in  orchards 
where  spraying  or  dusting  has  not  been  regularly  practiced,  and 
there  are  large  quantities  of  mummied  fruits  on  the  ground  and 
in  the  trees  to  spread  the  disease  early  in  the  season. 

Peach  Scab: — Peach  scab  does  the  larger  part  of  its  damage 
on  the  fruit,  but  the  fungus  infects  the  twigs  and  leaves  as  well. 
It  is  from  the  twigs  that  the  scab  fungus  is  spread  to  the  fruit  by 
the  spores  falling  and  being  washed  onto  them  by  rain.  In  this 
connection  it  is  interesting  to  note  that  scab  spots  are  always  on 
the  upper  surface  of  the  fruit.  Like  many  fungous  diseases  an 
important  factor  in  scab  control  is  to  prevent  it  from  getting  a 
start  in  the  orchard.  If  an  orchard  is  well  sprayed  or  dusted 
from  the  start,  scab  probably  will  not  be  especially  abundant. 


2  26       connecticut  experiment  station  bulletin  235. 

Summary. 

1.  Dusting  experiments  in  comparison  with  spraying"  were  con- 

ducted in  Connecticut  in  1921  in  four  apple  orchards  con- 
taining 757  trees,  and  in  two  peach  orchards  containing  263 
trees.  This  involved  the  scoring  of  150,296  apples,  equiva- 
lent to  about  334  barrels,  and  120,063  peaches,  or  about 
1,715  baskets. 

2.  The  dusts  were  all  applied  with  Niagara  dusting  machines, 

and  the  sprays  with  Friend  and  Arlington  X.  L.  power 
sprayers.     In  each  case  two  treatments  were  given  after 
blossoming  on  apples,  and  three  treatments  on  peaches. 

3.  The  dusts  used  in  the  apple  orchards  were  the  sulphur-lead 

dust,  sulphur-lead-nicotine  dust,  and  Sanders'  dust.  The 
liquid  spray  used  for  comparison  in  all  apple  orchards  con- 
tained liquid  lime-sulphur,  lead  arsenate  and  nicotine  sul- 
phate. In  one  orchard  comparative  tests  were  made 
between  liquid  lime-sulphur,  dry  lime-sulphur,  B.  T.  S.,  and 
Bordeaux  mixture,  with  lead  arsenate  added  to  each. 

4.  In  nearly  all  cases  the  best  apples  were  obtained  from  the 

sprayed  plots.  Both  spray  and  dust  gave  fairly  good  con- 
trol as  regards  codling  moth,  and  other  chewing  insects ; 
neither  controlled  curculio ;  the  spray  was  more  effective  in 
controlling  the  fungous  diseases.  In  the  sprayed  orchard 
dry  lime-sulphur  gave  a  larger  percentage  of  good  fruit 
than  liquid  lime-sulphur,  B.  T.  S.,  or  Bordeaux  mixture. 

5.  The  chief  pests  attacking  the  fruit  in  these  apple  orchards  in 

1 92 1  were  codling  moth,  plum  curculio,  apple  maggot, 
various  chewing  insects,  aphids,  red  bug,  scab,  black  rot, 
fruit  speck  and  sooty  blotch. 

6.  On  peaches  the  only  spray  was  atomic  sulphur,  and  the  dusts 

were  sulphur,  and  sulphur-lime-lead  arsenate  dust. 

7.  In  all  the  peach  orchards  the  dusted  plots  gave  slightly  better 

fruit  than  the  sprayed  plots.  Peach  scab  and  brown  rot 
were  controlled  by  both  dust  and  spray. 

8.  The  chief  pests  attacking  the  fruit  in  these  peach  orchards  in 

1 92 1  were  curculio,  brown  rot  and  peach  scab. 

9.  At  present  dusting  is  more  costly  than  spraying  in  both  peach 

and  apple  orchards. 


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